feat: add PowderDiffractionGenerator and methods for printing information

.github/workflows/check-news-item.yml

@@ -3,7 +3,7 @@ name: Check for News
 on:
   pull_request_target:
     branches:
-      - main  # GitHub does not evaluate expressions in trigger filters; edit this value if your base branch is not main
+      - main # GitHub does not evaluate expressions in trigger filters; edit this value if your base branch is not main
 
 jobs:
   check-news-item:

.github/workflows/tests-on-pr.yml

@@ -11,6 +11,8 @@ jobs:
       project: diffpy.cmirietveld
       c_extension: false
       headless: false
-      run: python -m pip install git+https://github.com/diffpy/pyobjcryst.git@d6a1279a26b9b1e6e303d103935b4469c5a62e41 --no-deps
+      run: |
+        python -m pip install git+https://github.com/diffpy/pyobjcryst.git@main --no-deps
+        python -m pip install diffpy.cmistructure --no-deps
     secrets:
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}

cookiecutter.json

@@ -14,7 +14,7 @@
   "project_short_description": "A pack for diffpy.cmi that allows it to do Rietveld refinement of powder diffraction data",
   "project_keywords": "diffraction, PDF, X-ray, neutron, Rietveld",
   "minimum_supported_python_version": "3.12",
-  "maximum_supported_python_version": "3.14",
+  "maximum_supported_python_version": "3.13",
   "project_needs_c_code_compiled": "No",
   "project_has_gui_tests": "No"
 }

docs/source/getting-started.rst

@@ -38,12 +38,12 @@ Here is how you can write a block of code in the documentation. You can use the
 .. code-block:: bash
 
     # Create a new environment, without build dependencies (pure Python package)
-    conda create -n <package_name>-env python=3.14 \
+    conda create -n <package_name>-env python=3.13 \
         --file requirements/tests.txt \
         --file requirements/conda.txt
 
     # Create a new environment, with build dependencies (non-pure Python package)
-    conda create -n <package_name>-env python=3.14 \
+    conda create -n <package_name>-env python=3.13 \
         --file requirements/tests.txt \
         --file requirements/conda.txt \
         --file requirements/build.txt

news/powder-diffraction-generator.rst

@@ -0,0 +1,26 @@
+**Added:**
+
+* Add ``PowderDiffractionGenerator``, which calculates one phase's Bragg intensity with pyobjcryst from a structure set with ``set_structure`` (a pyobjcryst ``Crystal``, the path to a CIF file or a ParameterSet), a peak profile set with ``set_peak_profile`` and an instrument set with ``set_instrument``, and a refinable ``scale``. It has no default peak profile or instrument, so all three must be set before a pattern is calculated.
+* Add ``PowderDiffractionGenerator.print_info``, which prints the generator's structure, instrument and peak profile with their settings and Parameter values.
+* Add ``Component.get_settings``, which returns a component's settings for showing to a user, and its ``ConstantWavelengthInstrument`` version, which lists the radiation type, the x-ray source or Kalpha1/Kalpha2 wavelengths, and the polarization rate.
+* Warn when ``set_structure``, ``set_peak_profile`` or ``set_instrument`` replaces a structure or component whose Parameters are used in a fit recipe.
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* <news item>
+
+**Security:**
+
+* <news item>

pyproject.toml

@@ -16,7 +16,7 @@ maintainers = [
 description = "A pack for diffpy.cmi that allows it to do Rietveld refinement of powder diffraction data"
 keywords = ['diffraction', 'PDF', 'X-ray', 'neutron', 'Rietveld']
 readme = "README.rst"
-requires-python = ">=3.12, <3.15"
+requires-python = ">=3.12, <3.14"
 classifiers = [
         'Development Status :: 5 - Production/Stable',
         'Environment :: Console',
@@ -29,7 +29,6 @@ classifiers = [
         'Operating System :: Unix',
         'Programming Language :: Python :: 3.12',
         'Programming Language :: Python :: 3.13',
-        'Programming Language :: Python :: 3.14',
         'Topic :: Scientific/Engineering :: Physics',
         'Topic :: Scientific/Engineering :: Chemistry',
 ]

requirements/pip.txt

@@ -1,3 +1,4 @@
 numpy
 diffpy.srfit
+diffpy.cmistructure
 pyobjcryst

src/diffpy/cmirietveld/__init__.py

@@ -4,15 +4,17 @@
 # (c) 2026 diffpy.cmirietveld contributors.
 # All rights reserved.
 #
-# File coded by: Caden Myers, members of the Billinge group, and contributors to the diffpy.cmirietveld project.
+# File coded by: Caden Myers, members of the Billinge group, and
+# contributors to the diffpy.cmirietveld project.
 #
 # See GitHub contributions for a more detailed list of contributors.
 # https://github.com/diffpy/diffpy.cmirietveld/graphs/contributors
 #
 # See LICENSE.rst for license information.
 #
 ##############################################################################
-"""A pack for diffpy.cmi that allows it to do Rietveld refinement of powder diffraction data"""
+"""A pack for diffpy.cmi that allows it to do Rietveld refinement of
+powder diffraction data."""
 
 # package version
 from diffpy.cmirietveld.version import __version__  # noqa

src/diffpy/cmirietveld/component.py

@@ -114,6 +114,23 @@ def mark_settings_changed(self):
         self._settings_version += 1
         self._flush(other=(self,))
 
+    def get_settings(self):
+        """Return the settings of the component, for showing to a user.
+
+        A generator's ``print_info`` shows them next to the Parameters.
+        A component with settings overrides this to list the settings in
+        use, each under the name of the setter argument that sets it, so
+        a user sees what to pass to change it.
+
+        Returns
+        -------
+        dict of str to object
+            The value of each setting in use, by name. It is empty for a
+            component without settings.
+        """
+        settings = {}
+        return settings
+
     def install(self, pattern, diffraction):
         """Set the model up in one generator.
 

src/diffpy/cmirietveld/instruments.py

@@ -365,6 +365,33 @@ def set_polarization(self, polarization_rate):
         self._polarization_rate = polarization_rate
         self.mark_settings_changed()
 
+    def get_settings(self):
+        """Return the settings in use, for showing to a user.
+
+        The radiation type and the polarization rate are always listed.
+        A tube adds ``xray_source`` and ``kalpha2_ratio``, and explicit
+        wavelengths add ``kalpha1``, ``kalpha2`` and ``kalpha2_ratio``.
+        A single wavelength adds nothing, since it is the ``wavelength``
+        Parameter.
+
+        Returns
+        -------
+        dict of str to object
+            The value of each setting in use, by the name of the setter
+            argument that sets it.
+        """
+        settings = {"radiation_type": self._radiation_type}
+        if self._xray_source is not None:
+            settings["xray_source"] = self._xray_source
+            settings["kalpha2_ratio"] = self._kalpha2_ratio
+        elif self._kalpha_wavelengths is not None:
+            kalpha1, kalpha2 = self._kalpha_wavelengths
+            settings["kalpha1"] = kalpha1
+            settings["kalpha2"] = kalpha2
+            settings["kalpha2_ratio"] = self._kalpha2_ratio
+        settings["polarization_rate"] = self._polarization_rate
+        return settings
+
     def install(self, pattern, diffraction):
         """Set the radiation, wavelengths and polarization of one
         generator.